Jet and rocket engine blast and sound suppressing means



Dec. 28, 1965 E. l. WAGNER 3,226,063

JET AND ROCKET ENGINE BLAST AND SOUND SUPPRESSING MEANS Filed July 14,1964 United States Patent C) s Claims. (Cl. 244-114) My presentinvention relates to an airport facility and more particularly to a jetnoise and blast suppressing means for use in running up jet engines of ajet propelled aircraft and is a substitute for my prior abandonedapplication S.N. 198,326, iiled May 28, 1962, and entitled Jet EngineBlast and Sound Suppressing Means.

An object of the invention is to provide a blast and sound waveintercepting means which may be employed to avoid and/or reduce otherobjectionable conditions now prevalent at airports located in closeproximity to residential and like areas.

Another object of the invention is to provide a gas blast and sound waveintercepting means which may be installed and operated at various pointsabout an airport during the running up period as is now generallypracticed prior to putting the power plant of a jet propelled aircraftinto flight.

A further object of the invention is to provide a blast intercepting andsound reducing means for use in testing and/or running up the jet engineof an aircraft which is in the form of an underground mufflerarrangement in which the blast gases are exhausted below the surface ofthe airport and at a point remote from the aircraft.

Another object of the invention is to provide a gas blast interceptingand sound wave intercepting baille in combination with a subterraneanexhaust passageway that may be used as a means for warming up an airportrunway surface as a means for preventing the accumulation of ice andsnow thereupon as often occurs in some areas during the winter months.

Other objects and advantages will be in part evident to those skilled inthis art and in part more particularly pointed out hereinafter in thefollowing description taken in connection with the accompanying drawingwherein there is shown by way of illustration and not of limitationpreferred embodiments ofthe invention.

In the drawing:

FIGURE 1 is a vertical fragmentary and sectionalized view showing myinvention with a blast fence similar to that disclosed and claimed in myprior patent,

FIGURE 2 is a similar fragmentary View showing a modified form of theinvention,

FIGURE 3 is a fragmentary sectional view showing a further modificationof the invention, and

FIGURE 4 is a view looking in direction of arrows along line 4 4 ofFIGURE 3.

With the advent of jet propelled aircraft there has developed anecessity for longer runways at airports and often these extensions haveencroached upon residential areas, where due to the increase in noiseincidental to the operation of jet aircraft there has developed aconsiderable objection to this noise by the citizenry of manycommunities. As a solution of the problem of excessive noise during therequired run-up period many airports have installed different types ofso-called blast fences which of necessity are located along the borderline of the airport area. These fences are generally only high enough tointercept the blast and being stationary the aircraft to be run up mustbe maneuvered into blast intercepting relationship with these fences andas a result the aircraft must be backed into position by a towingvehicle. While the present blast fences do prevent some of theobjetcionable blast from escaping to the surrounding area there stillremains an objectionable amount of noise and turbulence and the bestpresent solution appears to be an extremely high fence. Many newlydeveloped areas that are rapidly springing up around and about airportareas which in the early days, due to the cost of land, were generallylocated at the outskirts of large metropolitan areas and with theincrease in population in the suburban areas a reduction of theannoyance to these communities is therefore a problem which must beconsidered and solved, otherwise future airports will have to be locatedmiles from the centers of population.

In my prior Patent No. 3,017,146, granted January 16, 1962, and entitledJet Engine Blast Fence, I have shown and claimed a blast interceptingbaffle or fence that can be installed at any point upon an airportsurface and over which an aircraft can be moved into jet blastintercepting relationship without requiring any backing or othercomplicated maneuvering of the aircraft into an effective run-upposition with respect to the fence. While these devices are effective asa blast intercepting means they have been found to fall short of asolution to the excessive noise problem. It is therefore a primaryobject of my present invention to provide a combined blast and soundwave intercepting means by which the sound wave .producing blast of ajet engine is directed into a subsurface chamber with subterranean soundmufiiing means and exhausted remote from the area in which the jetengine is operating.

For a more detailed description of the invention reference is now madeto the accompanying drawing wherein like numerals refer to like partsthroughout the several views.

In the several figures of drawing the numeral 10 designates generally anairport surface over which jet and other type planes 11 are operated. Inthe FIGURES 1 and 2, the plane 11 is shown as having a jet type engine12 only one of which is here shown. It is therefore to be understoodthat where more than one jet engine 12 is located at opposite sides ofthe aircraft one or more of my proposed blast and sound interceptingdevices may be positioned at points to align with the engines at theopposite sides of the aircraft. In this figure, the airport surface 10is shown as having subsurface chamber 13 over which there is a platform14 having a portion of its leading edge in the form of an open grilllike structure 15 over which an aircraft may move. At the outer edge ofthe grill-like structure 15 there is an open laterally extending slot 16through which an arcuate batlie or -fence-like member 17 is adapted tomove to its operative position as here shown or into an inoperativeposition within the subchamber 13. In this arrangement, like thatdisclosed in my prior patent, the bafiie number 17 is carried by a crankarm 18 that has a gear sector 19 which engages a worm gear 20 that isdriven by an electric motor or other means 21. The subsurface chamber 13is of sufficient capacity to receive any normal blast of gas withoutcreating a back pressure and extending horizontally therefrom there is asubterranean tunnel 22 which may be of any length that will bedetermined by the point of iinal exhaust of the blast of hot gasses tothe atmosphere. In this showing the outlet or discharge end of thesubterranean tunnel 22 is shown as having a protective grill 23thereover, but as an alternative a stack 24 of any desired height mightbe positioned over this exhaust outlet to discharge the hot gasses andother debris into the atmosphere at a level above the airport surface.While the subsurface chamber 13 with the blast intercepting baffle orfence 17 and the subterranean tunnel 22 leading therefrom will operateto a degree as a sound controlling means, particularly where thesubterranean tunnel 22 is of some considerable length or is extended ina tortuous path beneath a runway as a means for warming up the surfacefor a more effective sound suppressing performance my inventioncontemplates the installation of a sound wave intercepting means ormuiller within the subterranean tunnel 22. As for the muiller 25, it isto be understood that the showings and locations thereof as herepresented are purely diagrammatic and that the type or design of mullleris of no particular moment except that it should operate to reduce thesound generated by the jet blast to a tolerable level.

Reference is now made to FIGURE 2 of the drawing, wherein there is showna blast intercepting baille 26 that is pivotally mounted upon anoperating shaft 27 located at the leading edge of the subsurface chamber13. This shaft 27 may be operated to raise the baille 26 into itsoperative position by an electric motor as shown in FIG- URE 1 of thedrawing. In this instance the baille 26 has depending skirt-like sides28 so that when the baille 26 is elevated as shown it will be in theform of an inverted scoop-like structure which will operate to directthe blast of hot gasses from the jet engine 12 into the chamber 13 andwhen lowered form a cover for the chamber over which an aircraft mayfreely move. The chamber 13 is also shown as having a forward extensionor reverberation chamber 29 which will allow for expansion of the blastgases. This chamber 29 is provided with a manhole cover 32 and a ladder33 through which access may be had for the purpose of removing anydebris or soot deposit which may accumulate therein. At the other end ofthe subterranean tunnel 22 there is a suction type blower 3i) which isadapted to create a reduced pressure within the charn.

ber 13 that will operate to draw an additional amount of cool free airfrom the surrounding intake area that will cool and chill the blast ofgas and thus help to improve the sound muflling eilect of the baille 26.While the blower 3i) is here shown and described as connected to alateral manifold conduit 31 into which any number of the subterraneantunnels 22 may be connected, it is conceivable that a blower 30 may beassociated with each of the subterranean tunnels 22. In this arrangementunlike that shown in FIGURE l of the drawing, the bafile 26 of itself,when in its inoperative position, will be ilush with the airport surfaceand thus form a platform over the subsurface chamber 13 over which theaircraft may move and as a result there is no need for a protectivegrill over the open top of the chamber 13. When a number of these soundintercepting baffles are used with at least one such baille on each sideof the airplane body the subterranean tunnels 22 may exhaustindependently of each other, but in a larger installation it iscontemplated that a number of these subterranean tunnels 22 mayterminate in the laterally extending manifold type conduit 31 under theairport surface that will exhaust the gasses into the atmosphere orthorugh the blower 3i) at a point far removed from the warming up areaof the airport.

Reference is now made to FIGURES 3 and 4 of the drawing showing afurther modiiied form which the blast fence and sound wave interceptingbaille may take. In this arrangement the baille or fence designated bythe numeral 34 is in the form of a semi-spherical clam shell shaped hoodthat is pivotally mounted upon a shaft 35 at the trailing .side of theopen topped subsurface chamber 13. In this instance the hood 34 carriesa worm gear sector 36 which is in mesh with a worm 37 that is driven bythe motor 21. At this point it should be stated that the motor 21 isshown as having conductors 38 that will be connected through a suitablecontrol switch with a source of electric power. Such a control switchmay be operated Aeither manually or through an automatic treddle switchas indicated in my prior patent. In this instance the subsurface chamber13 is contoured to accommodate the baille 34 and the face or open sideof the hood-like baille 34, has a series of spaced louvers 39 whichprovide a grill-like supporting surface ilush with the airport surfacelil over which a plane may move when the hood is in its inoperativeposition. In this instance the spaced louvers 39 are shown as having areinforced stay 40 intermediate their ends.

When elevated into their operative positions the several baflles orblast intercepting members 17, 26 and 34 will act to intercept anddirect the blast of hot gases from the jet engine downwardly into thesubsurface chambers 13 associated therewith. When the muillerarrangements are employed as here shown, the resultant sound producingcompressional waves and the blast of gas from the jet engine will bedirected to the subterranean tunnel 22 and coincidentally should asuction type blower 3i) or other means be connected to the tunnel 22 afurther sound reducing effect will result from the admixture of the hotblast gases with the inducted ilow of fresh air sucked into the chamber13 and the tunnel 22 by the blower 30.

With the arrangement as above described it will be apparent that inaddition to muflling the sound in terms of decibel units and avoidingturbulence above the airport surface my invention also provides a meansby which the energy of the jet may also be converted to further usefulpurpose. For example, by extending the subterranean tunnels 22 into agrid conilguration the heat of the jet blast might be used to raise thetemperature of the runway surface during the winter months with theresult that an accumulation of ice and snow could be avoided. As afurther imrpovcment I have in FIGURES 1 and 3 of the drawings shown thesubterranean tunnel 22 and the chamber 13 as having a means providing afine spray or curtain of water 41 that will function to settle andprevent any soot from being exhausted from the tunnels 22 and settlingin the surrounding neighborhoods.

While I have, for the sake of clearness and in order to disclose myinvention so that the same can be readily understood, described andillustrated speciiic forms and arrangements, I desire to have itunderstood that this invention is not limited to the specific formsdisclosed, but may be embodied in other ways that will suggestthemselves to persons skilled in the art. It is believed that thisinvention is new and all such changes as come Within the scope of theappended claims are to be considered as part of this invention.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1. In a gas blast and sound wave suppressing means for the jet engine ofa stationary aircraft with the jet operating in a horizontal plane overan airport area, the combination of an airport area having an open topsubsurface chamber over which a jet propelled aircraft may bepositioned, an inverted scoop-like jet blast intercepting baillenormally located within said chamber at the open top of said chamber,means adapted and arranged to elevate said blast intercepting baillefrom an inoperative position within said chamber to blast and sound waveintercepting relationship for directing the blast of a jet engine intosaid chamber, a subterranean tunnel leading from said chamber and underthe airport area through which the blast of gas from the jet engine isexhausted from said chamber at a point removed `from said chamber, andcharacterized'by the fact that said blast intercepting baille will forma cover over said chamber when in its inoperative position within saidchamber.

2. In a gas blast and sound suppressing means for use with a stationaryjet engine running up at an airport, the combination of an airport areahaving a subsurface chamber with an open top at the surface of anairport area,

a horizontally directed blast intercepting baille means located in aninoperative position at the open top of said subsurface chamber fordirecting a blast of gas from a jet engine downwardly and into saidchamber, a subterranean tunnel leading from said chamber to a remotepoint through which the blast from a jet engine entering said chamberwill be exhausted at a point remote from tion within said chamber to anoperative blast and sound wave intercepting position above saidsubsurface chamber, characterized by the -fact that said blastintercepting bathe means, when in in its inoperative position will forma closure for said subsurface chamber over which an aircraft may moveand a sound muiiling and hot gas cooling means mounted within saidsubterranean tunnel.

3. In a hot gas blast and sound wave suppressing means for aircrafthaving a plurality of jet or rocket engines with jets operating in ahorizontal plane parallel with an airport area, the combination of anairport area having a plurality of subsurface chambers, blastintercepting means for directing the exhaust of a jet engine into eachof said subsurface chambers, an independent subterranean tunnel leadingfrom each of said chambers to a point remote from said blastintercepting means through which the blast from the jet engine will bedischarged from said subsurface chambers, and a laterally extendingtunnel forming a manifold conduit to which each of said independentsubterranean tunnels are connected for exhausting the hot gases fromsaid chambers at la common point remote from said aircraft.

4. The invention as described in claim 1, characterized by the further-fact that said blast intercepting baille is in the form of an invertedflat bottom lscoop pivotally mounted at the leading side of saidsubsurface chamber with pending arcuate sides which when in itsinoperative position Will cover and close the entire area of the openinginto said subsurface chamber and when in its operative position willdirect the blast of the jet engine into said subsurface chamber.

5. The invention `as defined in claim 1, characterized by the furtherfact that said blast intercepting baille is in the form of asemispherical hood pivotly mounted at the trailing side of said chamberand having louvers over its open blast intercepting side forming asupport over which an airplane may move when said means is in itsinoperative position,

6. In a jet engine blast and sound suppressing means for airport-s,the-combination of an airport area having an open top subsurfacechamber, blast intercepting means for directing the exhaust of a jetengine into said subsurface chamber, -an independent subterranean tunnelleading from said subsurface chamber to a point remote from said blastintercepting means through which the blast of gas from the jet engine isconducted from said subsurface chamber, and means operatingindependently of said blast of jet gasesfor maintaining an inducedcirculation of hot jet gases and a How of surrounding air through saidsubterranean tunnel, whereby the blast of hot gases of the jet willcombine with the induced flow of free cool air sucked in and circulatingthrough said chamber and the subterranean tn nnel by said last means.

7. The invention as defined in claim 3, characterized by the' "fact that"said subterraneantunnels have means associated therewith and forming awater curtain to sep-arate soot and heavy particles from said blast.

8. The invention as set forth in claim 6, characterized by the fact thatthe independent subterranean tunnel leading from said subsurface chamberis extended and disposed in a grid-like pattern beneath a runway of theairport, whereby heat of the gas jets collected in said subsurfacechamber will heat the runway to prevent the accumulation of ice and snowand/or dry the runway following a rainy spell.

References Cited by the Examiner UNITED STATES PATENTS 2,358,868 9/1944Marx 98-115 2,674,335 4/ 1954 Lemmerman 244-114 2,692,024 10/1954Burdett et a1 244-114 2,733,668 2/ 1956 Pfetzing 244-114 3,017,1461/1962 Wagner 244-114 FOREIGN PATENTS 1,186,310 2/1959 France.

MILTON BUCHLER, Primary Examiner.

L. C. HALL, Assistant Examiner.

3. IN A HOT GAS BLAST AND SOUND WAVE SUPPRESSING MEANS FOR AIRCRAFTHAVING A PLURALITY OF JET OR ROCKET ENGINES WITH JETS OPERATING IN AHORIZONTAL PLANE PARALLEL WITH AN AIRPORT AREA, THE COMBINATION OF ANAIRPORT AREA HAVING A PLURALITY OF SUBSURFACE CHAMBERS, BLASTINTERCEPTING MEANS FOR DIRECTING THE EXHAUST OF A JET ENGINE INTO EACHOF SAID SUBSURFACE CHAMBERS, AN INDEPENDENT SUBTERRANEAN TUNNEL LEADINGFROM EACH OF SAID CHAMBERS TO A POINT REMOTE FROM SAID BLASTINTERCEPTING MEANS THROUGH WHICH THE BLAST FROM THE JET ENGINE WILL BEDISCHARGED FROM SAID SUBSURFACE CHAMBERS, AND A LATERALLY EXTENDINGTUNNEL FORMING A MANIFOLD CONDUIT TO WHICH EACH OF SAID INDEPENDENTSUBTERRANEAN TUNNELS ARE CONNECTED FOR EXHAUSTING THE HOT GASES FROMSAID CHAMBERS AT A COMMON POINT REMOTE FROM SAID AIRCRAFT.